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App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 53 · 40 questions
TalentJR

Developer's tip (When this, do that): Event → handler → action: “on tap, do this”. The handler runs once for every tap. Counter: start + taps × step. A limit stops it growing; on = !on flips ON / OFF.

NameDateTime takenScore ___ / 40
  1. 1.👆 What kind of event is this: one second passes? (a) a text event (b) a timer event (c) a load event (d) a tap event
  2. 2.True or false: the screen first opens is a tap event. (a) False (b) True
  3. 3.👆 The user taps the button 3 times. What number does the label show now?
    let score = 0;
    button.onTap = function () {
      score = score + 3;
      label.text = score;
    };
  4. 4.👆 What kind of event is this: the user taps Play? (a) a text event (b) a tap event (c) a load event (d) a timer event
  5. 5.👆 What kind of event is this: the user presses Save? (a) a load event (b) a timer event (c) a tap event (d) a text event
  6. 6.👆 The user types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    };     (a) Well done, nameBox.text! (b) Well done! (c) Zoya (d) Well done, Zoya!
  7. 7.👆 The user types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Hello, nameBox.text! (b) Zoya (c) Hello! (d) Hello, Zoya!
  8. 8.True or false: the user presses Save is a tap event. (a) False (b) True
  9. 9.👆 The user types Zoya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hi, " + nameBox.text + "!";
    };     (a) Hi, Zoya! (b) Zoya (c) Hi, nameBox.text! (d) Hi!
  10. 10.👆 The user taps the button 5 times. What number does the label show now?
    let coins = 3;
    button.onTap = function () {
      coins = coins + 1;
      label.text = coins;
    };
  11. 11.👆 A tap handler runs how many times if the user taps 4 times? (a) 0 (b) 8 (c) 1 (d) 4
  12. 12.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Well done, " + nameBox.text + "!";
    };     (a) Arjun (b) Well done, nameBox.text! (c) Well done, Arjun! (d) Well done!
  13. 13.👆 The user taps the button 3 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    };     (a) ON (b) OFF
  14. 14.👆 Which of these is an event? (a) the user taps a button (b) the font size (c) a list of names (d) the icon colour
  15. 15.👆 The user taps the button 4 times. What number does the label show now?
    let score = 7;
    button.onTap = function () {
      score = score + 4;
      label.text = score;
    };
  16. 16.👆 The user taps the button 3 times. What number does the label show now?
    let points = 3;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };
  17. 17.👆 The user types Meera in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Hello! (b) Hello, Meera! (c) Hello, nameBox.text! (d) Meera
  18. 18.True or false: a finger hits Like is a tap event. (a) False (b) True
  19. 19.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hi, " + nameBox.text + "!";
    };     (a) Hi! (b) Arjun (c) Hi, Arjun! (d) Hi, nameBox.text!
  20. 20.👆 What kind of event is this: the user types a letter? (a) a timer event (b) a load event (c) a text event (d) a tap event
  21. 21.👆 “On tap → do this” links an event to ___. (a) a web address (b) an action (c) a font (d) a charger
  22. 22.True or false: the app starts up is a tap event. (a) True (b) False
  23. 23.True or false: a 5-minute alarm ends is a timer event. (a) True (b) False
  24. 24.👆 The user taps the button 7 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    };     (a) ON (b) OFF
  25. 25.👆 The user taps the button 5 times. What number does the label show now?
    let score = 4;
    button.onTap = function () {
      score = score + 1;
      label.text = score;
    };
  26. 26.👆 The user taps the button 2 times. What number does the label show now?
    let lives = 5;
    button.onTap = function () {
      lives = lives + 5;
      label.text = lives;
    };
  27. 27.👆 The user taps the button 3 times. What number does the label show now?
    let points = 4;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };
  28. 28.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  29. 29.👆 The user taps the button 3 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 4) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  30. 30.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  31. 31.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
  32. 32.👆 What kind of event is this: a countdown hits zero? (a) a load event (b) a tap event (c) a text event (d) a timer event
  33. 33.👆 The user types Riya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    };     (a) Welcome! (b) Welcome, Riya! (c) Riya (d) Welcome, nameBox.text!
  34. 34.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    };     (a) Hello! (b) Hello, nameBox.text! (c) Arjun (d) Hello, Arjun!
  35. 35.True or false: one second passes is a tap event. (a) True (b) False
  36. 36.👆 The user taps the button 4 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    };     (a) OFF (b) ON
  37. 37.👆 The user taps the button 3 times. What number does the label show now?
    let points = 1;
    button.onTap = function () {
      points = points + 3;
      label.text = points;
    };
  38. 38.👆 The user taps the button 5 times. What number does the label show now?
    let points = 0;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };
  39. 39.True or false: the app starts up is a text event. (a) True (b) False
  40. 40.👆 The user taps the button 8 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };

Answer key

  1. a timer event
  2. False
  3. 9
  4. a tap event
  5. a tap event
  6. Well done, Zoya!
  7. Hello, Zoya!
  8. True
  9. Hi, Zoya!
  10. 8
  11. 4
  12. Well done, Arjun!
  13. ON
  14. the user taps a button
  15. 23
  16. 6
  17. Hello, Meera!
  18. True
  19. Hi, Arjun!
  20. a text event
  21. an action
  22. False
  23. True
  24. ON
  25. 9
  26. 15
  27. 7
  28. 4
  29. 3
  30. 2
  31. 3
  32. a timer event
  33. Welcome, Riya!
  34. Hello, Arjun!
  35. False
  36. OFF
  37. 10
  38. 5
  39. False
  40. 5

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